perm.cpp

来自「本文件为C++数据结构源代码」· C++ 代码 · 共 40 行

// output all permutations of n elements

#include <iostream.h>
#include "swap.h"

template<class T>
void Perm(T list[], int k, int m)
{// Generate all permutations of list[k:m].
   int i;
   if (k == m) 
   {// list[k:m] has one permutation, output it
	   	//	cout<<"k=m="<<k<<'\n';
		cout<<"recursive end  ";

                for (i = 0; i <= k; i++)
                   cout << list[i];
                cout << endl;
   }
   else  // list[k:m] has more than one permutation
         // generate these recursively 
         for (i = k; i <= m; i++)
		 {
			//cout<<"recursive\n";
            Swap(list[k], list[i]);
			//cout<<"list="<<list<<'\n';
			//cout<<"========\n";
            Perm(list, k+1, m);
			//ut<<"i="<<i<<"  k="<<k<<"  m="<<m<<'\n';
            //Swap(list[k], list[i]);
         }
}

void main(void)
{
   char a[] = {'1', '2', '3', '4'};
   int n = 3;
   cout << "The permutations of 123 are" << endl;
   Perm(a, 0, 2);
}